Summary

Fixes #366 by indexing explicit TypeScript module extensions (.mts and .cts) anywhere CodeGraph already treats .ts files as TypeScript source.

Note: .mjs / .cjs were already present in the JavaScript extension map before this PR; the missing coverage here was the TypeScript ESM/CJS pair.

Changes

• add .mts and .cts to the scanner/language extension map as TypeScript
• include .mts, .cts, index.mts, and index.cts in TypeScript import resolution
• update Express and NestJS framework extractors so route files using .mts / .cts are not skipped
• extend NestJS convention detection for files like *.controller.mts and *.module.cts
• add regression coverage for language detection, scanning, full indexing, import resolution, Express extraction, and NestJS detection/extraction

Validation

• npm ci
• npm run build
• npm test -- __tests__/frameworks.test.ts __tests__/extraction.test.ts __tests__/resolution.test.ts -t "(explicit TypeScript module extensions|TypeScript ESM files with \.mts|include explicit TypeScript module extensions|routes from \.mts|HTTP routes from \.mts|controller\.mts)"

The broader targeted run npm test -- __tests__/frameworks.test.ts __tests__/extraction.test.ts __tests__/resolution.test.ts currently passes 425/426 tests on my Windows machine and fails only in the existing C/C++ include end-to-end cleanup path with EBUSY: resource busy or locked, unlink ...\\.codegraph\\codegraph.db; the new .mts / .cts coverage above passes.